Sunday, February 4, 2018

Reflections on Pandora's Lab

Published in Skeptical Briefs volume 27, number 1, 2017.
by Felipe Nogueira

Resultado de imagemIn my last column, we briefly saw that Dr. Paul Offit’ latest book is Pandora’s Lab. As the subtitles explains is about Seven Stories of Science Gone Wrong. The book theme is simple: even though science has done good in the world, every possible invention might have bad consequences. If we accept new discoveries at face value, or to better put it, without the skepticism that science itself has taught us, we might, even with the opposite intention, doing harm. In some cases, avoidable harms; in other cases even more harm than good.

“Science can be Pandora’s beautiful box”, writes Offit. The seven stories covered in the book exemplify it very well. What connected those stories, besides science going wrong, is that they started in history, but their impact can be felt until today. Thus, as Offit shows in the final chapter, their lesson is still unlearned.

The lesson of vilifying saturated fat as the cause of heart disease still lives with us today. As clear explained in the book, heart disease or atherosclerosis happens when either of the coronaries arteries is blocked, interrupting the blood flow, damaging the heart, which occasionally might result in death.  The hypothesis that diet impacts heart diseases, recollects Offit, started in 1913 when a Russian study found that rabbits fed large quantities of foods rich in cholesterol (milk and egg yolks) developed atherosclerosis. Thus, the study’s author hypothesized that heart disease might be controlled by diet, specifically, by eating less cholesterol.

Another relevant study was done by Ancel Keys, who in 1950 compared people’s diet in several different countries. He found that countries with greater amount of fat in peoples’ diet, such as Finland, had higher incidence of heart disease. As such, he was the first person to use the term “heart-healthy diet”, urging Americans to restrict their fat intake. In 1961, the American Heart Association recommended to not eat more than 300 mg of daily cholesterol. There was only one problem with these recommendations: “scientific data on the relationship between fat consumption and human health remained, at best, ambiguous”, in Offit’s own words.

While data weren’t clear for radical interventions, restricting diet fat became government policy. Another crusader against fat was Senator George McGovern, who founded a nutrition committee responsible for a report wrote by politicians, instead of nutrition scientists or specialists.

In the 1980s, a non-governmental company called Center for Science in the Public Interest (CSPI) target restaurants and other food companies that used saturated fat based oils. This was a response to several studies that found saturated fat as the culprit of heart disease and that unsaturated fats were good for health. That’s what led us to the great margarine mistake. Following the push against saturated fat, the public reduced the amount of butter consumed, replacing it with margarine. Restaurants and food supply also made changes. They started using partially hydrogenated vegetable oils. As Offit put it, “In the 1980s, partially hydrogenated vegetable oils became the single most product for all baking and frying”.

Foods containing animal fats, such as butter and those oils previously used by industry, are rich in saturated fat. In contrast, margarine (at the time) and partially hydrogenated vegetable oils have great quantities of trans unsaturated fat, or trans-fat. In the 1980s and 1990s, studies linked partially hydrogenated vegetable oils with heart disease. Offit is crystal clear:
“The Harvard School of public health later estimated that eliminating trans fats from the American diet would prevent 250,000 heart attacks and related deaths every year!

Unlike studies of total fat, total cholesterol and unsaturated fat – where findings had been contradictory or inconclusive – no researcher has ever published a paper showing that trans fats are anything other than one of the most harmful products ever made.”
By trying to make us healthier, we ended up creating a much bigger problem. We didn’t know if trans-fat were safe or not, but our desperation to remove saturated fat from the diet certainly has led us astray: “in 2006, an article in the New England Journal Of Medicine declared ‘On a per calorie basis, trans fat appear to increase the risk of coronary heart disease more than any other macronutrient.’”

If that mistake was not enough, Offit brilliantly remember our desire to cure or treat mental illness was even more tragic. In attempt to understand the function of brain areas related to memory tasks, two researchers removed the frontal lobes of two chimpanzees. After the procedure, both chimps didn't remember how to get food. So, the researchers believed frontal lobes were responsible for creating and storing recent memories. But something else had happened. It seemed that one of the chimps didn't care for her recent memory limitation, as if she had "joined a happiness cult", in the words of one of researchers. They believed they had invented a treatment for anxiety.

It didn't require much time for someone trying this procedure called lobotomies in humans. In the late 1930s, several countries like performed lobotomies. One responsible for the apparent success of lobotomies was the neurologist Egas Moniz, who published a long monograph describing the procedure results in his 20 patients. Moniz reported improvements in more than half of it, even though adverse events like vomiting, diarrhea, nystagmus, and disturbed orientation of time and space happened. Surprisingly, Moniz was awarded the Sweden's Nobel Prize for his invention. The consequence was nothing to be awarded for: within four decades, 40,000 lobotomies were performed in the world.

The United States also had their lobotomy pusher: Walter Freeman. His "insight" was making a much more fast procedure, using electroshock for anesthesia and an ice pick. In 1950, Freeman wrote a book reporting the results of many of his “ice pick lobotomies”. While patients had several adverse events (as had happened with Moniz's patients), Freeman concluded his invention was successful. But Offit is clear about the patients:
"would lie in their bed like 'wax dummies' and have to be turned constantly by visiting nurses or family members to keep from getting bedsores. All were profoundly inddiferent to their surroundings. They didn't seem to care about anything. Worse, they had lost any sense of decorum". 
Despite serious adverse events (3% died from bleeding and other 3% faced permanent seizures), no medical society or organization stood up against lobotomies. According to Offit, it was the invention and use of psychoactive drugs that lessen the number lobotomies performed.

In a page-turner way, Offit tell us more five lessons of the past. God’s Own Medicine, or the story about the creation and use of opioid pain-killers, appeared in the latest issue of Skeptical Inquirer. We can learn the lesson from those stories to apply them to the present future.

That's what Offit does in the final chapter, for example discussing the problem of overdiagnosis and overtreatment with cancer screening programs. We must recognize as Offit explains that cancer's definition is changing. Not all of the detected cancers are going to kill us. Screening with PSA-test made prostate cancer the most commonly diagnosed non-skin cancer in the United States. But the risk of death due to prostate cancer remains unchanged in the last ten years. Critically, in men with 60 years or more that died from other causes, autopsies found prostate cancer in half of them. A similar situation is seemed in thyroid cancers, which are found in autopsies in one-third of people that had died from something else. The screening for breast cancer, another that in Brazil has a dedicated month to its promotion and awareness, it’s just a bit better because it saves some lives, but not many lives we’d think or like. Only 8 women of 122 benefit from it. The problem is what happened with the others: mastectomy, radiation therapy, chemotherapy with no evidence of benefit. Alarmingly, it’s estimated that 1.3 million women had been diagnosed with a breast cancer that would never killed them.

One clear lesson is to be cautions of anecdotes. Those pushers for lobotomies believed their procedure was saving lives. That’s why we need careful and controlled studies to evaluate the efficacy and safety of interventions.  So, Pandora’s Lab main lesson is to apply the skepticism even to science’s new inventions. Actually, accepting new inventions coming from science or not with face value is, in fact, not scientifically. The book beautiful reminds us that one of the big lessons of science is the skepticism and the importance in the promotion of science and critical thinking we do in CSI. The conclusion:
we need to approach all scientific advances cautiously and with eyes wide open – and to make sure that we learn from our mistakes and aren’t paralyzed by them.  

Saturday, February 3, 2018

To Be More Skeptical about Anti-Vaccination and Vitamins Supplements.


An Interview with Paul Offit
by Felipe Nogueira


Dr. Paul Offit is a pediatrician, the Chief of the Division of Infectious Diseases of the Children's Hospital of Philadelphia, and was the co-inventor of the rotavirus vaccine. He wrote several books about the importance of vaccines, clarifying the risks, which is often misunderstood. For example, the anti-vaccination movement insists that MMR vaccine causes autism. However, that relationship was already analyzed scientifically and we know it's wrong. In his book Do You Believe in Magic?, Offit makes a critical analysis of alternative medicine and the use of large dose of vitamins supplements. It’s important to raise the awareness about the vitamins supplements: it’s unregulated industry that claims vitamins supplements prevent disease. However, several studies [1-3] say most supplements do not prevent disease and some, such as vitamin E and beta-carotene [4], can increase the risk of cancer and mortality. Paul Offit’s website is www.paul-offit.com

Nogueira: Can you pinpoint when the anti-vaccination movement started? 
Offit: I think it started with the first vaccine. The smallpox vaccine was developed by Edward Jennen in 1700s. There was violent opposition to the vaccine in the early 1800s because that vaccine was mandated. I think the professional anti-vaccine people, like National Vaccine Information Center, Moms Against Mercury, Safeminds, and Generation Rescue, will say they would stop their anti-vaccine efforts if you simply make vaccines optional.

Nogueira: What exactly is the risk of Guillain-Barré syndrome [5] (GBS) after influenza vaccine? 
Offit: We can say with confidence that the 1976 swine flu vaccine had a risk of GBS in 1 per 100.000 who were given the vaccine. It’s not clear that since then any vaccine causes GBS. CDC and other groups that tried to categorize this always say that we cannot say is more common than 1 per million. The people are left with this vague notion that vaccine might cause GBS, but since the 1976 swine flu vaccine there is no clear evidence that it has.

Nogueira: If a vaccine causes a symptom, usually the disease the vaccine tries to prevent causes the same symptom. Can you clarify?
Offit: The best example is thrombocytopenia, which is low platelets level. There are a couple of studies and they all have been consistent and reproducible: the measles vaccine causes thrombocytopenia in 1 per 25-30 recipients. A measles virus also causes thrombocytopenia, but it is far more common. Another example: from 8 to 12 days after receiving chicken-pox vaccine, one can get a mild chicken-pox rash with 5 blisters, but sometimes can be 30 blisters. But chicken-pox natural infection can cause 300 to 500 blisters.

Nogueira: Knowing that MMR vaccine does not cause autism, how dangerous is to widespread information not corroborated by science?
Offit: I think once you scare people, it's hard to unscare them; once you open the Pandora’s box, it's hard to close it. The question was raised by Andrew Wakefield in 1998 with his publication in The Lancet, which wasn't a study. It was a simple case series: 8 children who had received the vaccine and developed symptoms of autism within 1 month. There are now 12 studies, looking to large number of people who did and didn't get the vaccine to answer the question "are you at a greater risk of having autism if you receive MMR vaccine?" The answer has been very reproducible: no. I think people are far more compelled by anecdote than they are by statistics. If Jenny McCarthy gets on Oprah and says "I watch my son get this vaccine, I watch his soul leave his eyes" and she cries, that's very compelling. A scientist on the show would say "fair question: could the vaccine cause autism?  Is this a causal effect relationship? Is this just a temporal effect or it is a plausible effect?" This is a scientific question and it has been answered in a scientific venue. But how do you trump the anecdote with science? The media became critical and they're not great at it.

Nogueira: Moving into vitamins supplements, when this idea begun? 
Offit: We need vitamins, no doubt it. If we don’t get enough of it from diet, we suffer diseases like pellagra, scurvy and rickets.[6] But we crossed the line from certain amount is good to therefore more would be better. That’s not true. Once you’re above the protective levels, you don’t need to be above of it. And I think the “big push” for supplements came in 1970s with Linus Pauling, who won Nobel Prizes in Chemistry and Peace. He was a strong voice and used to push vitamins supplements. Some of the earlier supplements were called Linus Pauling vitamins.

Nogueira: What about the risks of taking vitamin E? 
Offit: What amazes me about the vitamin E story is that there is a preparation of vitamin E that said "natural E 1000". If you look on the back label, it said that it had 3333% of the recommend daily allowance. You would have to eat about 1650 almonds, which are good source of vitamin E, to get the same amount from one gel capsule. That's not a natural thing to do. And if you take large doses of vitamin A, E or beta-carotene for prolonged period of time, you increase your risk of cancer and heart disease and potentially shorten your life. Those data are clear; there are twenty studies now that show that.
      
Nogueira: There is an article discussing that laboratory cut-off values for vitamin D are  not evidence-based. What can you say about it?
Offit: You’re right. Suddenly in the United States everybody has become vitamin D deficient. Certainly, it’s not because there’s been an outbreak of rickets; that hasn’t happened. It’s because of serum tests. I think what is considered normal values are not validated. Because of incorrect levels, all my friends tell me their doctors prescribed vitamin D for them. I like to think this is fad and will pass in a few years, because we’re doing no good and potentially some harm.    

Nogueira: Do you think there is enough evidence for vitamin D supplementation to prevent falls or fractures?
Offit: The U.S. Preventive Services Task Force (USPSTF) had at one point supported the use of vitamin D specially to prevent osteoporosis. The bone gets thinning in older people, so when they fall, they’re more likely to have fractures. Postmenopausal women are more likely to have these fractures. Then, vitamin D was recommended, since it helps to increase the uptake of calcium in the intestinal tract. However, with more data available, USPSTF does not recommend it anymore, since there is no clear evidence that postmenopausal woman or older people benefit from the intake of vitamin D or calcium.     

Nogueira: Where do you think came from this notion that vitamin supplements are natural? 
Offit: I give credit to the industry, which has been able to sell itself as natural. The nutraceutical and dietary supplements industry sell their supplements “as all natural, it can’t hurt you and it’s being made by old hippies”. This is not true. Pfizer and Hoffman-LaRoche are major players in dietary supplement game. It’s an unregulated industry with no obligation to support its claims. And, in United States, they have enough political influence to keep the FDA away from regulating them. Also, it’s very hard to be vitamin deficient; everything is supplemented. For example, it’s hard to suffer from folic acid deficiency in US, because grains, cereals, and pastas are supplemented with folic acid.

Nogueira: Your latest book is Bad Faith. What’s all about it?
Offit: It’s about how, in the United States, people have been able to use their faith to medically neglect their children. I think people should not be able to use the law to medically neglect their child. For example, 47 states have religious exemptions for vaccines. So, the book’s message is “we should not allow people in this country to use religion to put children in harm’s way.”

Nogueira: Have you planned a next book?
Offit: I have a new book coming out in April. The title is Pandora’s lab. Seven Stories of Science Gone Wrong. It’s about scientific discoveries that change the world for the worst.

Nogueira: Thanks for this thoughtful interview.  


Notes/References:

1. Fortman, S., et al. 2013. “Vitamin and Mineral Supplements in the Primary Prevention of Cardiovascular Disease and Cancer: An Updated Systematic Review for the U.S. Preventive Services Task Force. Annals of Internal Medicine,159 (12):824-834. 

2. Guallar, E., et al. 2013. “Enough is Enough. Stop Wasting Money on Vitamin and Mineral Supplements Annals of Internal Medicine,159 (12):850-851-851

3. Autier, P., et al 2014. “Vitamin D status and ill health: a systematic review”. The Lancet Diabetes & Endocrinology, Volume 2, Issue 1, pp 76-89.

4. Bjelakovic, G., et al 2012. “Antioxidant supplements for prevention of mortality in healthy and patients with various diseases”. The Cochorane Library, March, published online.

5. Guillain-Barré syndrome (GBS) is an autoimmune disease that attacks nerves cells causing muscle weakness and often paralysis. According to the CDC, approximately 3000 to 6000 people develop GBS each year in United States. Infection by Campylobacter jenuni, influenza and other infections are risk factors for GBS. More recently, countries with zika virus outbreak reported increased numbers of GBS cases.  For more information, visit the following CDC page: http://www.cdc.gov/flu/protect/vaccine/guillainbarre.htm 

6. Pellagra, scurvy and rickets are caused by deficiency of niacin (vitamin B3), vitamin C, and vitamin D respectively. 

Reflections on Krauss’s The Greatest Story Ever Told—So Far

by Felipe Nogueira


In the Summer 2016 issue of Skeptical Briefs, this column featured an interview with theoretical physicist Lawrence Krauss, who briefly mentioned his new popular-science book. The Greatest Story Ever Told—So Far was published by Atria Books in the beginning of March. It’s about the greatest intellectual journey ever taken by humans (so far) from Plato to the discovery of the Higgs’s boson.

Krauss begins by reminding us of Plato’s Allegory of the Cave. As the allegory goes, people live imprisoned inside a cave only seeing its blank wall. The only thing those inside the cave see from the outside world is that wall, which is illuminated by a fire behind them, allowing moving shadows to appear. According to Plato, the prisoners of the cave consider the shadows part of the real world to the point of giving names to them.


This Allegory of the Cave brilliantly introduces the book. As Krauss uncovers through the book, a lot of what we learn about the universe, or the greatest story ever told so far, came from humans’ investigation about the nature of light.

Newton’s curiosity about light, Krauss argues, might have been motivated because it was a gift from God. This is not a mischaracterization, since Newton devoted much more time to writing about the “occult, alchemy, and searching for hidden meanings and codes in the Bible—focusing in particular on the Book of Revelation and mysteries associated with the ancient Temple of Solomon—than he did to writing about physics.” So, Krauss thinks it’s also reasonable to conclude that Newton’s primary interest was in theology.

Regarding light, Newton thought that it was made of individual particles he called “corpuscles.” Other natural philosophers, such as Descartes and Robert Hooke, did not share his view, considering that light was a wave. In their support, when passed through a prism, white light splits into the several different colors of rainbow.

Even against it, some of Newtown’s discoveries about light made more sense with the “wave theory of light.” He discovered, for example, that each color of light has a distinct angle at which it bends when passing through a prism. He also showed that colored light does not change its color, regardless of how many times it passes through a prism. All of this could be explained if white light is indeed a collection of different colors, but not if light is made of different-colored particles (as Newton thought).

The debate persisted for many years involving discoveries that seem unconnected to the nature of light, such as the connection between electricity and magnetism. As Krauss points out, “These two forces seem quite different, yet have odd similarities. Electric charges can attract or repel. So can magnets. Yet magnets always seem to have two poles, north and south, which cannot be isolated, while electric charges can individually be positive or negative.” To connect these forces required the work of Michael Faraday, the greatest experimental physicist of the nineteenth century. Faraday worked for years trying to see if magnetism could induce electricity, which he showed in 1831, allowing us to use electricity the way we do today, changing the world forever:


It is hard to imagine any discovery that is more deeply ingrained in the workings of modern society. But more deeply, what makes his contribution to our story so remarkable is that he discovered a missing piece of the puzzle that changed the way we think about virtually everything in the physical world today, starting with light itself. If Newton was the last of the magicians, Faraday was the last of the modern scientists to live in the dark, regarding light
The mystery of the connection between electricity and magnetism continued until 1865, when Maxwell published his complete set of equations, connecting these two apparently unconnected phenomena together in a formal theory. He also showed that oscillating charges produce an electromagnetic wave. Then, critically, Maxwell calculated the speed of the electromagnetic wave and he found out what was almost identical to the already known speed of light. Light is an electromagnetic wave.

There was a problem, however. Maxwell’s results concerning electromagnetic waves contradicted the properties of motion already established by Galileo many years before. If a ball is thrown with a speed of 10 mph inside a car moving at 15 mph, someone outside the car would measure the speed of the ball to be 25 mph (10 mph plus 15 mph). But what if instead of a ball inside the car, we have an oscillating charge? Maxwell calculated the speed of electromagnetic waves produced by oscillated charges measuring the strength of electricity and magnetism. Then, would someone outside the car measure the speed of electromagnetic waves from the oscillating charge to be different than what someone inside the car observes? If that’s the case, the observers would measure the strength of electricity and magnetism to be different from the other’s, allowing us to tell who is moving and who is not. But Galileo had shown this is impossible; there is no experiment anyone could perform that could tell if one is at rest or moving at a constant speed. Even though it’s a profound implication, Einstein was the one who realized it. The inconsistency is not just a thought experiment or between simple suppositions; both Galileo’s and Maxwell’s results have been verified by experiment. As Krauss remind us all, “rules that have been established on the bases of experiment cannot easily be tossed aside.” That’s why we needed Einstein’s genius to reconcile those notions.

Einstein’s great solution was that, as Krauss explains, “the two different observers must both measure distances and/or times differently from each other in just such a way that light, at least, would traverse that same measured distance in the same measured time for both observers.” In Einstein’s theory of relativity, space and time measurements are observer dependent.

Motion, electricity, magnetism, and relativity are all connected. That is just the beginning. The book continues to detail those hidden realities of our world, connecting in interesting ways many other physical phenomena, from the double-slit experiment and the rise of quantum mechanics (which uncovered the individual particles that light is made of) to unification of electromagnetism and weak force to superconductivity and the Higgs’s boson.

Were it not for the progress of science—reason and experiment, instead of Plato’s pure thought—we would not uncover many parts of the hidden realties; we would still be inside of a Plato’s cave. And the job of scientists, as Krauss argues, is to see what is behind the shadows, separating illusion from reality.

As the title suggests, the story is not finished: “Every day that we discover something new and surprising, the story gets even better,” says Krauss. Every page of the book you turn, it gets better. Krauss certainly has made a great contribution by describing the hidden realities in his fascinating book.

Friday, February 2, 2018

Reflections on Sean Carroll’s The Big Picture

by Felipe Nogueira

Sean Carroll is a theoretical physicist at the California Institute of Technologies. He has also dedicated a considerable amount of time to science popularization through his books, such as From Eternity to Here and The Particle at the End of the Universe, and debates, for example with theologian William Lane Craig.

Carroll’s latest book is The Big Picture: On the Origins of Life, Meaning and the Universe Itself. Published by Dutton, the book came out in May 2016. With that title, it’s right to assume that Carroll covered many topics in the book. A look at the table of contents finds six parts, with topics such as “The Funda­mental Nature of Real­ity,” “Interpreting Quan­­tum Mechanics,” and “The Origin and Pur­pose of Life.” But in short, the book is about poetic naturalism.

Naturalism asserts, as Carroll puts it, that “there is only one world, the natural world, exhibiting patterns we call “the laws of nature,” which are “discoverable by the methods of science and empirical investigation.” He makes it crystal clear that within naturalism there is no space for the supernatural: “There is no separate realm of the supernatural, spiritual, or divine; nor is there any cosmic teleology or transcendent purpose inherent in the nature of the universe or in human life.”

And what is the natural world made of? Our deepest understanding of reality, or in other words, our fundamental ontology is The Core Theory, a better term coined by physicist Nobel Prize winner Frank Wilczek for the Standard Model of particle physics. “It’s the quantum field theory of the quarks, electrons, neutrinos, all the families of fermions, electromagnetism, gravity, the nuclear forces, and the Higgs,” Carroll explains. So on our most fundamental level we have a sparse ontology, containing several different entities.

The Core Theory also 
tells us something very im­portant about the world: there is no such thing as astrology and life after death. Carroll had written about this on his blog [1], and he repeats this spectacular argument again in the book. Using our fundamental ontology, the world, including our bodies, is made of particles interacting according to equations of the Core Theory. The important point here is what kind of particles is the soul made of? If souls are made of the same ordinary particles as human bodies, there is no afterlife. On the other hand, if they are made of a different particle, this certainly would require a new physics to describe the interaction between our bodies—collections of ordinary Core Theory particles—with the soul. But every experiment ever performed says the Core Theory provides the correct description of how its particles behave at everyday energies. We know it’s not a complete description of everything that exists in the world—for example, dark matter is not included in it—but it describes everything related to human beings. If it exists, an immaterial soul that interacts with our bodies would prove the Core Theory is not right at everyday energies; the Core Theory would then need to be modified to include how its particles interact with the soul. One cannot believe in the existence of the soul and also believe the Core Theory is the correct description of how particles behave at everyday energies. “There is no life after death. We each have a finite time as living creatures, and when it’s over, it’s over.” Carroll blows the hope for the soul away.

The same line of reasoning can be applied to astrology. The Core Theory particles make human beings interact with a few forces of nature: gravity, electromagnetism, and strong and weak nuclear forces. But the nuclear forces do not reach macroscopic scales, and gravity is too weak—gravitational force from other planets might be equivalent or even weaker than that of a person nearby. We’re left with electromagnetism, but it’s not difficult to think that any electromagnetic signal coming from other planets will be interfered with signals originated here on Earth.

This brings another important question: What about things that are not part of the Core Theory? Are they just illusions? No! These can be useful ideas to describe real phenomena that manifest at higher scales. Temperature and entropy, for example, are not part of our fundamental ontology, but they’re real; they are emergent phenomena.

This is why Carroll is a poetic naturalist, and he does a great job throughout the book of differentiating fundamental from emergent phenomena, highlighting that both are real. But poetic naturalism is bigger than that; it has space from moral values, even if they’re part of our deepest ontology and not emergent. For Carroll (although Sam Harris certainly disagrees [2]), morality is not something out there to be found and cannot be discovered by science, but it is not less important. Poetic naturalism embraces all these “views” together. In Carroll’s own words:

Within poetic naturalism we can distinguish among three different kinds of stories we can tell about the world. There is the deepest, most fundamental description we can imagine—the whole universe, exactly described in every microscopic detail. Modern science doesn’t know what that description actually is right now, but we presume that there at least is such an underlying reality. Then there are “emergent” or “effective” descriptions, valid within some limited domain. That’s where we talk about ships and people, macroscopic collections of stuff that we group into individual entities as part of this higher level vocabulary. Finally, there are values: concepts of right and wrong, purpose and duty, or beauty and ugliness. Unlike higher level scientific descriptions, these are not determined by the scientific goal of fitting the data. We have other goals: we want to be good people, get along with others, and find meaning in our lives. Figuring out the best way to talk about the world is an important part of working toward those goals.
To conclude, it’s a great book, covering a wide range of interesting topics. In fact, it’s impossible to fairly account for all the good stuff in the book in a short review like this. Go read it!

Notes

  1. http://www.preposterousuniverse.com/blog/2011/05/23/physics-and-the-immortality-of-the-soul/
  2. http://www.preposterousuniverse.com/blog/2010/03/29/sam-harris-responds/

Thursday, February 1, 2018

The discovery of gravitational waves. An interview with Lawrence Krauss

by Felipe Nogueira
published in Skeptical Briefs Volume 26.2, Summer 2016


On my previous column, I briefly covered the fascinating discovery of gravitational waves. For this this column, I had the opportunity to talk about it with Lawrence Krauss, a theoretical physicist and cosmologist at Arizona State University (ASU) and author of A Universe from Nothing.  

Nogueira: Can you explain briefly gravitational waves and general relativity? 
Krauss: General relativity is a theory of space and time. Einstein showed that matter affects the properties of space and time around it; space curves, expands, and contracts because of matter. A massive body affects the space around him and, when it moves, the massive body produces a disturbance of the space that can propagate out, like a ripple when you throw a stone in the water. In 1916, Einstein showed that such disturbance would propagate out and would be a wave, a gravitational wave. Just like electromagnetic waves happen when you jiggle a charge, a gravitational wave is a disturbance of space. That means the properties of space changes when a gravitational wave goes by. If there are gravitational waves in this room right now, the distance between my hands would be smaller, but my length would be longer, then in instants later, this changes: my length would contract and the distance between my hands would be longer, and so on. Einstein thought that gravitational waves would never be observed. He also retracted gravitational waves later on 1937, when he tried to solve the equations of gravitational waves and came up with an answer that didn’t make sense. He submitted the paper to Physical Review and it was rejected. He got upset, since he had never been peer-reviewed before. He said that he had sent the paper to be published, not to be reviewed. But it served him well, because before he could submit elsewhere, he and someone else realized the mistake in the paper and the final published version is correct. Thus, for a brief time, Einstein though gravitational waves didn't exist.

NogueiraEinstein also changed his mind about the cosmological constant, didn't he?
Krauss: He introduced the cosmological constant, because he thought the universe was static and he thought the cosmological constant would make the universe static. In fact, he was wrong on both grounds. The universe is not static and because of that Einstein said it was a big blunder to have the cosmological constant included. But it was a big blunder anyway, because a cosmological constant does not result in a static universe. It generally results a universe we live in now, which is exponentially expanding.

NogueiraAbout five years ago, we discovered the Higgs Boson. It was a major discovery as it's this discovery of gravitational waves. I have the impression that there was more excitement with this current discovery than with Higgs Boson. Is this impression correct? 
Krauss: I think it got more advance notice and I am partly responsible for that. But everything related to Einstein somehow capture the public imagination. Einstein predicted gravitational waves 100 years ago and Higgs predicted the Higgs' particle 50 years ago. The real difference is that the discovery of the Higgs boson is a major discovery of something very important in the Standard Model, but it doesn't guarantee that will be more discoveries or that would open up new windows beyond that. The discovery of gravitational waves was something like the telescope was just turned on: it was the first time that we had a machine that could do this, and we're pretty well certain that we will be able to use this over the next century as a probe of the universe. It's quite possible the machine that discovered the Higgs reveals to us more, but it's no guarantee. In contrast,  knowing that we have gravitational waves, it tell us that we will be able to see a lot more about the universe than we saw before.

NogueiraWhat kind of ideas might be tested using gravitational waves?
Krauss: We never measured general relativity in a strong regime near an event horizon, where space is highly curved. We never measured strong gravity gravity has always been week.  With these results, it looks like general relativity applies in those domains. So, we can extrapolate it to domains where space is curved and rolling like a boiling sea, and not as gentle ripples. This will be a good test of general relativity. As we probe the physics close to the event horizon, we'll learn the nature of black holes.  And who knows what else we'll learn? Every time we opened up a new window in the universe, we were surprised. So, I'll be surprised, if we are not surprised.

NogueiraA story circulated in Brazilian newspaper saying that this discovery would make time travel possible in 100 years. Time travel was also addressed by Kip Thorne at LIGO’s press conference. What can you comment about it?
Krauss: It has nothing to do with time travel. It means that we can explore general relativity in a regime where gravity is very strong and fields are very massive. But it doesn't tell us that we will be able to do time travel in any way; who said that doesn’t know what they're talking about. Kip Thorne was in an event called Einstein Legacy at ASU, which can be seen online [1]. Thorne made it clear he doesn't think time travel is possible, even though he spent time writing papers to see if it was possible.

NogueiraRegarding the non-scientist population, how can this discovery have an impact or to be relevant for them? 
Krauss: These two black-holes collided in a second and they emitted an energy equivalent three times the mass of the sum. This is more than the energy emitted by all the stars in the visible universe during that moment. Those kinds of things can amaze you. As I say, it tells us a little bit of what we came from and where we are going; it enhances our place in the universe. So, from a cultural perspective, it's part of the beauty of being human. It's not going to produce a better toaster, but the technology used on the experiment could be used on other things.

NogueiraHow LIGO experiment was done?
Krauss: The experiment is amazing. In order to detect gravitational waves, there are two arms perpendicular from each other in a detector. If a gravitational wave comes by, one arm will be shorter and the other will be longer, alternatively. To measure the length, a laser beam is emitted and travels until it reaches the end of the arm, then it bounces back. This is done in both arms. If one arm is shorter, the laser will take less time to travel it than in the other arm. That sounds easy, but they have to able to design a detector that can measure the difference in length between two four-kilometer long tunnels by a distance of one ten-thousandth the size of a proton. It's so small the quantum mechanical vibrations of the atoms in the mirror they used are much bigger than that. It's like measuring the distance between here and the nearest star with accuracy of the width of a human hair. It's an amazing bit of ingenuity, perseverance and technology; it's really beautiful!          

NogueiraIs this the last prediction to be discovered regarding general relativity? Even such, we know it's not the final answer. Why is that the case? 
Krauss: Gravitational waves were the last aspect of general relativity that needed to be tested directly; it's completely right.  And so is quantum mechanics; it has been tested so much that it's a fundamental theory. But we know that quantum mechanics and gravity don't work together. In very small scales, where quantum mechanics ideas are important and gravity is strong, the two don't go together; we know something has to give.    

NogueiraFor you, what would be the next most exciting discovery in physics? 
Krauss: The waves that have been seen are interesting, but for me it's much more interesting waves from the earliest moments of the Big Bang during inflation. We thought we had discovery it in the last year. We can look for their signature in cosmic background radiation coming from the big bang. If we can detect their signature, we will be able to probe the physics of the very early universe - the nature of quantum gravity itself. LIGO's detector is not sensitive to those waves from the big bang, but we might build big detectors in space that could be sensitive. I’ve written a paper with Nobel-prize winner Franck Wilczek showing that if you can measure gravitational waves from the Big Bang, they will prove gravitational waves is a quantum theory.  

NogueiraI know you have an upcoming book. What can you comment about it?
Krauss: It's called The Greatest Story Ever Told So Far and will come out probably on March 2017*. It's the story about the greatest intellectual journey humanity has ever taken, all the way from Plato to the Higgs. My last book discussed the question "why is there something rather than nothing" and this new one address the question "why we are here?" The new book was built up on a lecture with the same title, which is also available online [2], but of course there is a lot more on the book than in the lecture. The book also talked about the future based what we know with the discovery of the Higgs.   

[1] Einstein's Legacy, Celebrating 100 Years of General Relativity: An Origins Project Panel. https://origins.asu.edu/panel-einsteins-legacy-100-years-general-relativity

* Update: the book has been published. My review of the book was also published at Skeptical Briefs.